gt40 diff.

[Paolo-LoveGT40 Modelworks]

First of all sorry cause this post is a little technincal and my english will be even worse than usual, so sorry.

Being nut in those weeks for drift with my actual car (a rwd BMW 3 serie convertible) I am spending many huors in car cemetery seraching interesting parts as the limited slip differential.
Bmw made it as a very very expensive optional, and was only available from the beginning on the M3's.For all the other models it was an aftermarket part (nearly 3000 USD new)
That optional is too useful when car goes oversteering and u make turns drifting (I use 205/60 R15 old pirelli tires, hard as wood).
The limited slip is vital and too helpful also in hard climate condition as driving on snow with RWD cars, as BMW and Mercs.

Looking at the mechanic of the gt40s, she has a trasaxle, that should be an all-in with gear and diff.(I am quite sure that is really the most expensive part of the car, much more than the engine).
The transaxle also works as a limited slip differential?
Do not really think a car powerful as the 40 (also the smallest ones have 300 hp) dont have such part.

Hope u understand what I mean.
Please tell me more

 

[Ian K]

Paolo,

The various transaxle options all have limited slip options as far as I know.

The Porsche G50 series had some versions with built in LSD, but there
are aftermarket alternatives as well.

Quaife makes (or, perhaps, made) an LSD unit for the Renault UN1.

I believe the ZFs had LSD, at least as an option.

The ZFQ has an optional LSD if I am not mistaken.

And, I read that there was an LSD available for the Audi transaxles.

Does that answer your question?

Ian

 

[Mike Drew]

I believe the ZFs had LSD, at least as an option./QUOTE]

Yes, it's a standard feature on all ZF transaxles. :thumbsup:

 

[Paolo-LoveGT40 Modelworks]

yes, more or less yes.
Basically should be the porsche G55 gearbox with built in lsd.
Will try ask to my local porsche assistance point.

It is incredible bmw does not supply that too important optional neither in 330 ci e46 serie.
It is even a car of 1600 kilos with 230 hp...

It should be the mx5 miata coming with a lsd as standard optional, but it is a different type (bmw inside is different, we name it as "lamellare (bmw)" and "viscoso (mazda)"...dunno really how to traslate this in english, but think u understand)

Does maybe ferrari have gearboxes with lsd inside?
I understand now why this part comes so expensive.

 

[Ian K]

yes, more or less yes.
Basically should be the porsche G55 gearbox with built in lsd.
Will try ask to my local porsche assistance point.

It is incredible bmw does not supply that too important optional neither in 330 ci e46 serie.
It is even a car of 1600 kilos with 230 hp...

It should be the mx5 miata coming with a lsd as standard optional, but it is a different type (bmw inside is different, we name it as "lamellare (bmw)" and "viscoso (mazda)"...dunno really how to traslate this in english, but think u understand)

Does maybe ferrari have gearboxes with lsd inside?
I understand now why this part comes so expensive.

"lamellare (bmw)" is, I assume, would be clutch-type or possibly geared, i.e. a torque
sensitive LSD engaged by two (or more) mechanical parts. Quaife ATB, ZF, Porsche G50
series, etc.

"viscoso (mazda)" is, I assume, would be a fluid (viscous) speed sensitive LSD, where
as speed builds, the viscosity of the fluid changes, allowing the coupler to expand, causing
the two plates to connect. The fluid needs changing, as in the known case of the Miata,
if not, the LSD no longer functions properly and becomes effectively an open diff.

Ian

 

[EGLITOM]

For porsche gearboxes

it can be seen from the gearbox number if there is a LSD in there or not

A 1988-89 trans has a 12 digit code, such as 'G5000 1 J 00903'

* G5000 = trans type (see below)
* 1 = normal differential (0= no diff, 2= ZF ltd. slip diff)
* J = 1988 model (K= 1989)
* 00903 = serial number

There are also some aftermarket LSD availables : Guard Transmission, Drexler, Quaiffe
some of them are clutch plate style ones , others are ATB ( wormdrive design, Torsen) types.

Drexler is making excellent Diffs for BMW´s as well
Drexler Drivetrain - Drexler Sperrdifferenzial - Limited slip differential - Differenziali autobloccanti
scroll down the have the info also in italian

TOM

 

[Paolo-LoveGT40 Modelworks]

"lamellare (bmw)" is, I assume, would be clutch-type or possibly geared, i.e. a torque
sensitive LSD engaged by two (or more) mechanical parts. Quaife ATB, ZF, Porsche G50
series, etc.

"viscoso (mazda)" is, I assume, would be a fluid (viscous) speed sensitive LSD, where
as speed builds, the viscosity of the fluid changes, allowing the coupler to expand, causing
the two plates to connect. The fluid needs changing, as in the known case of the Miata,
if not, the LSD no longer functions properly and becomes effectively an open diff.

Ian

yes, correct.
unfortunately with BMWs is a mess to recognize the LSD from outisde.
The only visible difference is a big white S painted over the external box, and the only chance to afford one from scrapped cars is that the guy in car cemetery dunno what it is (but is very hard,and is also hard to find any first owner bimmer paying for such very expensive toy,imho too important with a rwd car).

Here some pics of the differentials.The first pic are 2 ones for e36. The left one is lsd, the other is free.
The open ones pics come from an E30

 

[Jim Rosenthal]

Ferraris have had limited-slip rear axle differentials since the fifties. I've seen them taken apart for overhaul. They used a sprag or over-running clutch arrangement, more or less, which had a ring of little metal blocks that looked like Chiclets, one ring per side, if memory serves. I don't know how well they worked (I remember someone telling me that the Chiclets could wear out and then the limited-slip feature didn't work so well) but I'm certain that they had it back then.

Good luck finding this kind of thing. LSD wouldn't have been special-ordered by a lot of folks for BMWs- they may have assumed it was already on the car- so the the short supply will push up demand. I know one of my old Mercedes has it, and the only way to tell is that there is a metal tag on the differential housing. Which, of course, could easily break off, and no one would know what was in there.

 

[Paolo-LoveGT40 Modelworks]

Good luck finding this kind of thing. LSD wouldn't have been special-ordered by a lot of folks for BMWs- they may have assumed it was already on the car- so the the short supply will push up demand. I know one of my old Mercedes has it, and the only way to tell is that there is a metal tag on the differential housing. Which, of course, could easily break off, and no one would know what was in there.

Exactly, also I think the same.
They never fit so many cause almost all owners believe it was already on (is the same with mercedes)
Noted all this cause recently had a ride with a friend exchanging with me the 330 ci convertible vs my e36 convertible.We try some drift cause the engine is very powerful,even if the e46 is really a pig, much more heavy than my car.
Was a mess to close correctly the turn, cause the car had the ugly attitude to go where she wants, while when I did the same with an m3 (both e36 and e46) it was a lot easyer, and all the manuvering was much more safer than with open diff.

My point is that I want to do this....easy and without rain :thumbsup: :
YouTube - bmw m3 drift

...and I would love to do it (or at least look someone doing this) with a Gt40

PS: Tom, maybe the S is the first letter of the word u use in german for the lsd.Am I wrong?

 

[Keith]

Hey Paulo, what year/model is your 3 Series?

What final drive ratio do you need i.e. 3.73 or 4.11 for example?

This is what you need:

They are rare but they can be had.

These people in the US might give you some good info:

diffsonline.com - Custom Geared BMW LSD Differentials

I also understand that AC Schnitzer do an LSD unit for 3 Series. Obviously you'll find them in Germany.

If you let me know the info I will see what I can find in the UK. I had a 3 series convertible too but it had LSD...

Drifting Paulo? Are you sure that's a proper macho Italian pursuit? I will NOT call it a sport.... :veryangry:

 

[Ron Earp]

:wrongforum:

Moving to the transaxle tech forum.

 

[Paolo-LoveGT40 Modelworks]

ooops...sorry Ron.

Btw your racing Miata has the standard LSD from mazda or did u change it?

 

[Ron Earp]

ooops...sorry Ron.

Btw your racing Miata has the standard LSD from mazda or did u change it?

Without reading the whole thread....

The viscous Mazda unit will get hot within a lap or two and behave like an open diff. The only purpose of this diff is to improve traction in rain/snow on a street car. It is not up to track work. Fine for street use, no go for track work. Had one, hated it, replaced it with the clutch pack.

Get a clutch type, torsen/quaife type, or even a welded over a viscous unit if you're headed for the track.

IMHO.

 

[Paolo-LoveGT40 Modelworks]

Hey Paulo, what year/model is your 3 Series?

What final drive ratio do you need i.e. 3.73 or 4.11 for example?

This is what you need:

They are rare but they can be had.

These people in the US might give you some good info:

diffsonline.com - Custom Geared BMW LSD Differentials

I also understand that AC Schnitzer do an LSD unit for 3 Series. Obviously you'll find them in Germany.

If you let me know the info I will see what I can find in the UK. I had a 3 series convertible too but it had LSD...

Drifting Paulo? Are you sure that's a proper macho Italian pursuit? I will NOT call it a sport.... :veryangry:

LOL, u are right Keith, its not a real sport,its just some fun.:laugh:
Hope not to bore the guys cause it is not a bmw forum, but quickly:
my actual car is a convertible 1998 e36 318.
The engine is tuned and I have the beauty of 160 hp under bonnet (is not so much power,I know).
Basically for THIS quiet car i look for an lsd just for more safety on the road.
It actually fits very nice wide tires, but no way to drift with theme (falken 255/45 r17 rear).
In the pics I have the Dunlop slick tires, blown during drifting.

Try look if u find something at a GOOD price (I am searching around 300 euros for not new items).
Note the e36 does not fit e30 lsd.
In the past I had an m3, but sold it to partially pay my house.I loved the stunning quality of old bmw's so I bought another one,even convertible (as u all wellknow e36's are the very last great quality cars done in Munchen).

btw, what 3 convertible do u have keith?

 

[Damian]

Wait who is looking for a diff from an e30M3 (U.S. 4.10) cause I got one. :thumbsup:

 

[Paolo-LoveGT40 Modelworks]

Without reading the whole thread....

The viscous Mazda unit will get hot within a lap or two and behave like an open diff. The only purpose of this diff is to improve traction in rain/snow on a street car. It is not up to track work. Fine for street use, no go for track work.

Get a clutch type, torsen/quaife type, or even a welded over a viscous unit if you're headed for the track.

IMHO.

ahhh, now I see.
A friend of mine owns a Miata anniversary edition (1.8i).
Dunno the american name, but is the second serie, the one with front similar to Viper.
IMHO a very cool little light car, with 140 hp, enough to have a lot of fun over 1000 kilos of vehicle.
While using her drifting we all noted more u go on ...more the diff seems tired and works as an open one. I understand now why !
Surely in racing u will have this problem after 2 or 3 laps.

what do u mean ron when u say "welded" diff. over the viscous unit?

I just saw some welded ones on bmw, but they use in stuntman show (even if I was definitely tempted to buy one open, and fix it...surely comes cheaper than find the good bmw original one).
If I forget I am going on the road with a welded diff I will be as Duke of hazzard in every turn .
Fun but surely dangerous

 

[Ron Earp]

a
While using her drifting we all noted more u go on ...more the diff seems tired and works as an open one. I understand now why !

You ought not be doing that car ballet anyhow....

 

[Ron Earp]

what do u mean ron when u say "welded" diff. over the viscous unit?

Welded diff. The carrier is welded up and there is no more differential action - both wheels spin at the same rate no matter what is going on. I've raced with one for a season and it was not as bad as I thought it was going to be. And in SOME cases I even preferred it over a clutch type or quaife, but overall I prefer the clutch type when properly adjusted.

 

[Paolo-LoveGT40 Modelworks]

Miata spirit:
YouTube - Miata drift compilation

Oh...so u raced with it welded (is then the same as for pure drifters) and it was not so bad... very very interesting !

have to understand if is tricky or not to do it alone in my garage.

 

[Ron Earp]

have to understand if is tricky or not to do it alone in my garage.

Depends on how well you can weld. I can tell you this - you do not want to have one of these let go whilst driving. They tend to do so rather violently and ruin your rear end.

Better would be to use a spool but I doubt these are commonly available for BMW diffs. Not too many drag race BMWs and the one I saw at the strip in the late 90s had a narrowed Ford 9" under an E30 chassis. No kidding.